Lubricant sealing device for a work feeding mechanism of a sewing machine

ABSTRACT

A lubricant seal member for a sewing machine carried on the feed bars that actuate the device for advancing a workpiece as it is sewn and disposed so as to prevent the leakage of lubricant from the source of drive for the feed bars to the workpiece advancing device.

United States Patent Mariorio Jan. 115, 1974 LUBRICANT SEALING DEVICEFOR A [56] References Cited ;S E OF A UNITED STATES PATENTS 1,673,1636/1928 Schmelzkopf 184/5 X [75] Inventor; Nerino Marforio, Milan, Italy1,906,728 5/1933 Van Duyn 184/5 2,707,093 4 1955 Bloss et a1.. 308/35 xAssigneel -p- Vlrgmm Rlmoldl & (30-, 3,515,444 6/1970 Grabner 308/35Milan, Italy 3,692,272 9/1972 Radke 308/35 x [22] Filed: Mar. 2, 1972[2]] A l N 231 276 Primary ExammerGeo V. Larkm [30] Foreign ApplicationPriority Data [57] ABSTRACT Mar. 29, 1971 Italy 22415 A/7l A lubricantsea] member f a Sewing machine v on the feed bars that actuate thedevice for advancing [52] [1.8. C1. 112/256, 277/174 a workpiece as it iSewn and disposed so as to prevent [51] Int. Cl D05b 71/00 the leakageof lubricant f the Source of drive f [58] Field 01 Search FS 6 13 1 0 0the feed bars to the workpiece advancing device. I i 1 1 3 Claims, 4Drawing Figures J 21 u '1 22 IT 23 V 5 sum 1 m5 PATENTEU JAN 15 I974 TUELUBRICANT SEALING DEVICE FOR A WORK FEEDING MECHANISM OF A SEWINGMACHINE SUMMARY OF THE INVENTION The present invention refers to alubricant sealing device for a work feeding mechanism of a sewingmachine.

As is well known, in some models of sewing machines the actuatingmechanisms and all surfaces subject to frictional engagement with otherparts of the machine must be subjected to an amount of lubricant whichnecessitates separating the area where the devices operate from the areawhere the stitching and the work feeding mechanisms operate so as toprevent the lubricant from contacting the feeding mechanism and beingabsorbed by the workpiece being sewn.

For this reason the frame of the machine has been fitted with a chamberin which there are mounted the actuating mechanisms for the feed dogs ofthe work feeding mechanism, which are spaced from the chamber andoperatively connected with the mechanisms by means of special feed bars.

The feed bars extend through a section of the chamber, which is disposedbetween the two areas and of a size to accommodate only the feed barsand prevent leakage of the lubricant from the chamber. With the feedbars arranged in this manner, the lubricant tends to leak out of thechamber through the working clearances for the feed bars during theirworking cycles and permits the escaped lubricant to flow towards thestitching mechanisms and the feed dogs.

The aim of the present invention is that of preventing leakage of thelubricant out of the chamber and thereby eliminate any possibility ofthe lubricant reaching and soiling the workpiece.

In order to reach this aim the technical problem to be solved was thatto provide a device capable of sealing the chamber while at the sametime permit the feed bars to function in a normal manner.

To solve this problem the invention provides a lubricant sealing elementfor a work feeding mechanism of a sewing machine comprising one or twofeed bars which are moveable alternatively in a horizontal and verticaldirection causing the feed dogs to travel in an elliptical pathwayduring their function of advancing the workpiece. The sealing elementincludes an aperture through which the feed bars extend and is of a sizewhich conforms to the cross-sectional configuration of the feed bars.The walls of this aperture being in frictional contact with the outersurfaces of the feed bars are effective in wiping the lubricant therefrom during their horizontal movement.

The advantage resulting from the present invention is the lubricantsealing element functioning in cooperation with the feed bars completelyseals the chamber and prevents the lubricant from leaking out along thefeed bars to the workpiece feeding mechanism.

Further aims and advantages of the invention will become more fullyapparent by reference to the appended claims and as the followingdetailed description proceeds in reference to the figures of drawingwherein:

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view in partialsection of a sewing machine to which the present invention isapplicable,

FIG. 2 is a sectional view taken along line lI-ll in FIG. 1,

FIG. 3 is a perspective view in exploded form of the device according tothe present invention, and

FIG. 4 is a perspective view of the device in the FIG. 2 shown assembledand its relationship to the feed bars.

DETAILED DESCRIPTION OF DRAWINGS For purpose of illustration, thepresent inventions shown mounted on an overlock industrial sewingmachine.

This machine is normally composed of a bed I (FIG. 1) fitted below witha reservoir 2 for the collection of the lubricant. A standard 3 ispositioned above the bed 1 and adjacent to a bed plate 4 on which thepiece to be sewn is caused to move.

These elements joined together form the frame of the sewing machine andhouse the required mechanisms and elements necessary for it to performits intended function.

Within the base 1 a rotatable main shaft 5 is journaled with one endthereof protruding from the frame on which is fixed a handwheel 6 fittedwith a belt pulley 7. The pulley 7 can be connected with a normaldriving motor (not illustrated).

On the other end the main shaft 5 terminates in a chamber 8 where itsupports the actuating mechanism 9 of the work feeding mechanism. Thismechanism includes an eccentric 10 fitted with a pitman 11 (FIGS. 1 and2) whose fulcrum is on an arm 12 of a rock shaft 13. Shaft 13 isprovided with another arm 14, similar to arm 12, which is connected bymeans of a link 15 with a feed bar 16 having a toothed feed dog 17 onits free end.

The feed bar 16 extends from the chamber 8 parallel with an offsetvertical partition 18 of the latter and po sitions the feed dog 17 in anarea spaced from said chamber.

In the area where the feed dog 17 operates a needle 19 (FIG. I) issupported by a needle clamp 20 and is alternatively moved in thewell-known manner along a substantially vertical rectilinear pathcausing it to pass through the bed plate 4 and intersects both paths ofthe well-known primary and secondary loopers 21 and 22 respectivelywhich cooperate with the needle to form the normal stitching pattern forthe overlock stitch.

The loopers are actuated by known mechanisms carried within the frameand for purpose of brevity the only parts shown are their supports 23and 24.

On the bed plate 4 there is also provided a presserfoot 25 cooperatingwith the feed dog 17 to move the piece forward as it is sewn by thestitching means. The cooperation between the presserfoot and the feeddog is made possible because the bed plate 4 includes a throat plate 26(FIG. 2) out of which the said feed dog periodically protrudes.

The actuating mechanism 9 reciprocates the feed bar 16 horizontally andby means of an eccentric 27 on sahft 5 which is operatively associatedwith said feed bar (FIG. 4) the latter is moved both horizontally andvertically simultaneously. This motion causes the feed dog carried onthe free end of the feed bar to move through an elliptical pathwayduring the performance of its intended function.

The elliptical movement of the feed dog 17 is arranged so that it movesupwardly to protrude through the forward portion of the throat plate 26to contact the sewn workpiece and then moves rearwardly sliding saidworkpiece to the rearward portion of the throat plate. The feed dog isthen lowered below the throat plate and moved forwardly to repeat thecycle.

The sewing machines of the above-mentioned type can also be fitted witha second work feeding mechanism which includes a second feed bar 28 witha feed dog 29 on its free end and which is disposed immediately adjacentto the first feed bar. The second feed bar is actuated by a link 31which is operatively connected to an arm 30 carried on the rock shaft13.

The structure of the second work feeding mechanism as well as itsoperation has not been described for it functions in the same manner asthe work feeding device described above.

The sewing machines to which the invention is applicable operate at highspeed, and the lubricating requirements for the various actuatingmechanisms causes a great quantity of lubricant to be circulated withinthe chamber 8.

To prevent the lubricant from leaking out of the chamber and movingalong the feed bars to the feed dogs, the partition 18 includes a recess18 in which there is assembled a lubricant sealing device 32 composed ofa support member 33 which has a conforming fit in recess 18' and whichis provided with a guide channel 34 (FIGS. 2 and 3) through which thetwo feed bars 16 and 28 extend. Obviously, when the machine is designedto have one feed bar only, the support member 33 will be replaced by asimilar one with a narrower central slot which conforms to the thicknessof one feed bar only.

The lubricant sealing device 32 is also composed of a guide element 35formed by two spaced parallel plates 36 having a configurationconforming to the upper ends of two upwardly directed spaced checks 37and forming the guide channel 34 therebetween. The two plates 36 areinterconnected by a crosspiece 38 from which two guides 39 and 40depend.

Guides 39 and 40 include integrally formed and vertically extendingpathways 41 and 42 respectively. The central slot 34 is formed toconform only to the width of the feed bars and clearance must beprovided in order for them to move vertically during the performance oftheir intended function.

To prevent the lubricant from escaping through the clearances providedto permit vertical movement of the feed bars, the lubricant sealingdevice 32 is also provided with a lubricant sealing element 43fabricated from a wear resistant organic sheet material such for exampleas sheet teflon or the like. The sealing element is relatively thin witha configuration that is substantially rectangular and is provided withan aperture 44 of a size that conforms to the outer dimension of across-section of the two feed bars or one only if the machine isdesigned for one feed dog only. In operating position, the feed barsextend through the aperture 44 of the sealing element 43.

To assemble the sealing element 43 onto the feed bars the lower part ofsaid element includes a reed plate 45 formed by a pair of spacedapertures 47 which are interconnected by a slit 46 a portion of whichcommunicates with the lower surface of aperture 44. By simply folding orflexing the sealing element 43 aperture 44 can be enlarged a sufficientamount so as to easily assemble over the ends of the feed bars.

After the sealing element 43 is assembled on the feed bars it isreleased and the elasticity thereof will cause it to return to itsinitial shape whereby the walls of the aperture 44 will make andmaintain frictional engagement with said feed bars. To prevent movementof the lubricant sealing element 43 during horizontal movement of thefeed bars, the sides thereof are assembled in the above-mentionedpathways 41 and 42 of the guide element 35 where it is free to followthe feed bars during their vertical movements only.

The feed bars move simultaneously within the lubricant sealing element43, which faces the slot 34 and is of sufficient size so as tocompletely seal any passage to the outside of the chamber 8 which isbeing formed within the slot and at the same time is effective in wipingthe lubricant from those portions of the feed bars within said chamber.The lubricant thus that is wiped from the feed bars drops down into thechamber 8 and only enough lubricant remains thereon to lubricate thosesurfaces in contact therewith.

When the lubricant sealing device is assembled, the guide element 35 isfixed by two screws 48 on the support member 33 that is in turn fixed inthe recess 18 by means of screws 49 (FIG. 2) inserted into holes 50. Asto what is described up to now, the support member 33 can be designedwith the central slot 34 which can accommodate one or two feed bars.Obviously the lubricant sealing element 43 can be provided with anaperture 44 of a size appropriate for the feed bar or feed bars on whichit is to be assembled. Additionally the sealing element 43 is easilyreplaced should wear develop due to continued frictional contact withthe feed bars.

I claim:

1. A lubricant sealing device for the workpiece feeding mechanism of asewing machine of the type having at least one feed bar movable in ahorizontal and vertical direction to define an elliptical pathway for atoothed feed dog carried thereon, the improvement comprising:

a. a support member having a guide channel within which movement of thefeed bar is guided;

b. a flexible lubricant sealing element having internal surfacesconforming to the cross sectional configuration of the feed bar definingan opening through which the latter extends;

c. guide means on said support member for permitting vertical movementonly of said sealing element during actuation of the feed bar.

2. The lubricant sealing device according to claim 1 wherein saidsealing element is fabricated from wear resistant organic sheetmaterial.

3. The lubricant sealing device according to claim 1 wherein said guidemeans includes means defining vertically disposed opposed pathwayswithin which the sides of said sealing element extend for guiding thelatter during its vertical movement by the feed bar.

1. A lubricant sealing device for the workpiece feeding mechanism of asewing machine of the type having at least one feed bar movable in ahorizontal and vertical direction to define an elliptical pathway for atoothed feed dog carried thereon, the improvement comprising: a. asupport member having a guide channel within which movement of the feedbar is guided; b. a flexible lubricant sealing element having internalsurfaces conforming to the cross sectional configuration of the feed bardefining an opening through which the latter extends; c. guide means onsaid support member for permitting vertical movement only of saidsealing element during actuation of the feed bar.
 2. The lubricantsealing device according to claim 1 wherein said sealing element isfabricated from wear resistant organic sheet material.
 3. The lubricantsealing device according to claim 1 wherein said guide means includesmeans defining vertically disposed opposed pathways within which thesides of said sealing element extend for guiding the latter during itsvertical movement by the feed bar.